北方一次暖区大暴雨强降水成因探讨

摘要

A severe typical warm sector torrential rain with the obvious mesoscale characteristics of long lasting and concentrating precipitation area attacked Huanghuai Region on July 7 2012.The formation of the warm sector torrential rain induced by the Huanghuai warm wind shear line is discussed based on con-ventional and unconventional observation data and NCEP analysis data.The results showed that the whole troposphere with high humidity is beneficial to weaken the lifting condition,enhance precipitation efficien-cy and formation of quasi-stationary mesoscale convective systems.Vertical wind shear in low troposphere and extra low-altitude j et flow are likely to play an important role in triggering and maintaining the convec-tion.Subsynoptic and mesoscale lift conditions such as surface wind convergence line,shear line at 850 hPa or 925 hPa and wind convergence brought by the low level jet can lead to the torrential rain. Meanwhile,the radar echo represents the backward propagation,train effects and tropical heavy rainfall characteristics.%提2012年7月7日黄淮出现一次典型暖区大暴雨过程，降水持续时间长、强度大和强降水范围集中，中尺度特征明显。本文通过常规和非常规观测、NCEP分析资料对该次黄淮暖切变线引发的豫东北、鲁南和苏北等地大暴雨天气过程的成因进行探讨，结果表明：整层高湿环境有利于降低暖区暴雨对抬升条件的要求、提高降水效率和局地不断产生中尺度对流系统；低层垂直风切变和超低空急流在对流触发和维持中可能有重要作用；次天气及以下尺度的抬升条件，如地面辐合线、925和850 hPa切变和低空急流出口区的风速辐合等均可导致强降水，降水落区一般位于低层多层风速辐合的叠置区；暖区暴雨的雷达回波具有明显的后向传播、列车效应和热带降水型特点。